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TONMO Supporter

Not that I'm aware of Nate (covering myself, just in case someone shows that they can in the future); they sure can sense vibration though.

Two structures in a squid referred to as statoliths (a bit like a fish's otoliths, which are sometimes referred to as 'ear bones') are used for balance/orientation in the water column (but not for hearing).
Cheers, O

Hatchling

Thanks for the prompt reply Steve. As a commercial squid fisherman in So. California (loligo opalescens) I've often noted a behavior wherein we'll toss seal bombs (large waterproof firecrackers) prior to setting (to ward away mammals) and they have virtually no visible response from the squid. This is when the squid are "floating" to our attracting lights by the tens of thousands and the only noticeable response is a quick jerk possibly due to the flash or sheer percussion. The occasional finfish unlucky enough to be within a meter or two ends up belly up presumably due to the blast disrupting his swim bladder. (sound like a guy who clubs baby seals don't I) Not sure if I understand your point that they're statoliths allow them to sense vibration but not sound as what is sound (particularly in water) if not vibration? My interest in this I should note is the potential self enrichment of attracting more squid by playing them a good polka (oxymoron?) Well if they can "hear" even a little does anyone know if they're jazz enthusiasts?

TONMO Supporter

A little Neil Diamond Serenade will lure them in, but that polka business for sure will frighten 'em off, quicker than clogs on a steel deck.

The squid statoliths are purely balance/orientation structures ... I shouldn't have mentioned 'earbones' at all (analogy with the fish's otolith). Interesting that the squid don't scatter with the old tuna/seal bomb equivalent to a greater extent. In a few months we'll be giving this jigging business a trial ourselves, so PLEASE stay around as I'm sure you'll have something way informative to contribute.
Cheers
Steve

Carefully evading the first question, for which I have no appropriate answer, and skipping to the next, responding with several queries myself, have you noticed any species other than Loligo being attracted to your lights? And, have you used different light intensities and colours yourself, and if so, noticed any difference in size-class or species composition of the catch? Another question - what sort of depths are you working over? And a fourth, do you find reduced captures/lesser attraction to the lights at different phases of the moon?

You'll have more applied experience than most with squid reactions to light intensity, and I'm interested in picking your brains.

Tintenfisch, I discussed this with the Dean of Science yesterday, and we concur in our belief that we introduce a new, prerequisite (as in compulsory) PhD paper at Uni just for you. Moreover, an A+ is required in both lecture and laboratory work in order to pass. The paper is titled "Appreciation of Neil Diamond 05.501", with course details to follow.
Toodles
O

TONMO Supporter

.... and I'm really hard when it comes to grades. I'll make her resit that exam each and every year until she succeeds (and if I keep failing her maybe she'll stay on longer). Just for the heck of it I think I'll give her a E- in 2003 anyway (that'll throw her in a spin!) 8)

Question:
Many times people have asked me if cephalopods can hear and at first I didn't know the answer. Since then I've read a study by Packard et al (1990) which indicates that cephalopods do hear low frequency sounds. Cephalopods have complex statocysts which also help them 'hear' (Budelmann).
Answer:
However, after a few pointers from Dr. Budelmann and further reading it appears that the answer is more complicated and depends on what your definition of hearing is. Using the following broad definition, hearing is the reception of vibratory stimuli of any kind and nature, provided that the sound source is away from the animals body, cephalopods can hear. Some other definitions of hearing require that the animal have an air filled cavity with sensors capable of detecting the pressure component of sound - something cephalopods do not have according to Budelmann (1996).

To me the arguement above is semantic - if they can detect sounds waves, they can hear. Your mileage may vary. In any case, this isn#t one of the senses they are known for. They don#t have organs for hearing but do have a latteral line system which might do the trick for detecing low frequency sounds.

Hatchling

i also fish for squid in so. california. i am very sure they can detect some kind of low frequency sound or vibration. there have been times when circling a school of squid that was attracted to a lightboat that they will actually follow us around. we ca see this on our sonar unit very visibly. also revving the engine up and down, on occasion has drawn the squid into a tighter school around the boat. every time we have a school of fish around the boat, the squid on the surface is always more dense on the port side. the only difference between each side of the boat is:1) the large generator we use is mounted below the water line on the port side 2)there is not a water overboard on that side.(water overboard is a hole 2 inches in diameter were sea water is pumped overboard after it has gone thru a cooling condenser. our discharge is 1 inch above the waterline) any questions or comments please reply thanks

TONMO Supporter

also revving the engine up and down, on occasion has drawn the squid into a tighter school around the boat. every time we have a school of fish around the boat, the squid on the surface is always more dense on the port side. the only difference between each side of the boat is:1) the large generator we use is mounted below the water line on the port side 2)there is not a water overboard on that side.(water overboard is a hole 2 inches in diameter were sea water is pumped overboard after it has gone thru a cooling condenser. our discharge is 1 inch above the waterline) any questions or comments please reply thanks

I don't know how I missed this post; sorry for the delay. So, there's absolutely no difference in lighting between port and starboard sides of the boat? It would be interesting to know what your bearing was, whether held constant/roughly so when fishing, because it may have had something to do with the position of the moon, or perhaps, depending on the time of night/tidal cycle/state of the tide, or the direction and/or speed of current/tidal flow (maybe surface currents were affected on one side of the vessel more so than the other) - do you work into or with the current, or fish on slack tide? I'm just searching for an alternative here to that of the generator alone. Is the generator emitting high or low frequency vibration?

Re the water overboard, our squid larvae concentrate around a spray bar that jets water into the tank (during the day), but at night tend to aggregate closest to a 40 watt light bulb that is wall-mounted closest to the other side of the tank (a few metres away from the spray bar); the latter could simply be an attraction to light, but the aggregation during the day beneath the spray jets has always intrigued me.

Hull/engine noise vibration has always been something that has concerned me greatly when accommodating squid in tanks welded or fitted to the deck. It would be interesting if you were to about ship 180 degrees and see if those squid still aggregated port side when next you're out.

Vampyroteuthis

Not that Iv heard of. Iv dissected Squid and iv read a LOT about Squid Biology and it is clear that Squid cannot hear and they have no hearing organs. Neither of the cephalopods have hearing organs. It was thought Octopus could hear but that was false. Mabye when they atrt to evolve thell somday have that unit to hear.